From: Florian Westphal <fw@strlen.de>
Date: Sat, 9 Apr 2022 13:58:25 +0000 (+0200)
Subject: evaluate: keep prefix expression length
X-Git-Tag: v1.0.3~38
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ae7d32fc36d4e8714b392670ff2fd6af8135a322;p=thirdparty%2Fnftables.git

evaluate: keep prefix expression length

Else, range_expr_value_high() will see a 0 length when doing:

mpz_init_bitmask(tmp, expr->len - expr->prefix_len);

This wasn't a problem so far because prefix expressions generated
from "string*" were never passed down to the prefix->range conversion
functions.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---

diff --git a/src/evaluate.c b/src/evaluate.c
index d5ae071a..a20cc396 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -347,6 +347,7 @@ static int expr_evaluate_string(struct eval_ctx *ctx, struct expr **exprp)
 	datatype_set(prefix, ctx->ectx.dtype);
 	prefix->flags |= EXPR_F_CONSTANT;
 	prefix->byteorder = BYTEORDER_HOST_ENDIAN;
+	prefix->len = expr->len;
 
 	expr_free(expr);
 	*exprp = prefix;
diff --git a/src/expression.c b/src/expression.c
index 9c9a7ced..deb649e1 100644
--- a/src/expression.c
+++ b/src/expression.c
@@ -1465,6 +1465,7 @@ void range_expr_value_high(mpz_t rop, const struct expr *expr)
 		return mpz_set(rop, expr->value);
 	case EXPR_PREFIX:
 		range_expr_value_low(rop, expr->prefix);
+		assert(expr->len >= expr->prefix_len);
 		mpz_init_bitmask(tmp, expr->len - expr->prefix_len);
 		mpz_add(rop, rop, tmp);
 		mpz_clear(tmp);